robertson



May 17, 1938. w. H. ROBERTSON' CASH REGISTER Original Filed Jan. 10,1930 2 Sheets-Sheet duo: (4:

May 17, 1938. H. ROBERTSON CASH REGISTER Original Filed Jan. 10, 1930 2Sheets-Sheet 2 FIG.

gnwmtoz William H. Robertson Hi8 dfliozmq Patented May 17, 1938 UNITEDSTATES CASH REGISTER William H. Robertson, Dayton, Ohio, assignor to TheNational Cash Register Company, Dayton, Ohio, a corporation of MarylandOriginal application January 10, 1930, Serial No. 419,938. Divided andthis application June 21, 1935, Serial No. 27,619. In Canada March 24,

11 Claims.

This, invention relates to printing mechanism for cash registers andlike machines, but more particularly to impression hammer controllingmechanism for machines of the type illustrated and described in LettersPatent of the United States No. 1,816,263, issued August 4, 1931, andUnited States Patent No. 1,929,652 issued October 10, 1933 both toWilliam H. Robertson, and, in application for Letters Patent of theUnited States, Serial Number 419,938 filed January 10, 1930 by William.H..-Robertson, now Patent No. 2,056,485. This application isa divisionof the above named application.

One object of this. invention is to provide machines. of the characterdisclosed in the above patents and application with mechanism to preventthe rebounding of the impression hammers and thereby preventing thepossibility of blurring the record material.

Another object is to contrive mechanism to govern the number ofimpression strokes the printing hammers make during, a single machineoperation.

Still another object is to devise mechanism to control the effectivenessof one of, two printing platens carried by one of the impressionhammers.

With these and incidental objects in view, the invention includescertain novel features of construction and combinations of parts, theessential elements of which are, set forth in appended claims and apreferred form or embodiment of which is hereinafter described withreference to the drawings which accompany and form a part of thisspecification.

In said drawings:

Fig. 1 is a side elevation as observed from the right of the machine,depicting the impression mechanism and the operating means therefor.

Fig. 2 is a detail view of the rebound preventing mechanism for theupper impression hammer.

Fig. 3 is a detail view of the rebound preventing mechanism for thelower impression hammer.

Fig. 4 is. a facsimile of a printed ticket or postage label issued bythe machine of this invention.

Fig. 5 is a side elevation of the mechanism for controlling theimpression strokes of the upper impression hammer,

50 Fig. 6 is a detail view of the operating mechanism associated withthe hammer disabling mechanism pictured in Fig. 5.

Fig. '7 is a top plan view of the upper impressio hammer and portrays inparticular the mechanism associated with the shiftable platen blockcarried by said hammer.

Fig. 8 is a facsimile of a fragment of a permanent detail strip used inthe machine of this invention. Fig. 8 also represents a fragment of anissuing detail strip which is identical in every way to the permanentdetail strip.

GENERAL DESCRIPTION The printing mechanism used in the machine chosen toillustrate one form of the present invention is identical with thatdisclosed in the parent application and includes two groups. of typecarriers simultaneously set by differential mechanism under control ofdepressed amount keys in adding operations and under control of thetotalizer wheels in totalizing operations. One printing hammer isprovided to take impressions from one group of type carriers on anissuing detail strip and another impression hammer is provided to take aplurality of impressions at each operation of the machine from the othergroup of type carriers, one of such impressions being made on an issuingticket and another on a permanent detail strip.

The lower hammer makes one printing stroke each machine operation toeffect a single impression on the issuing detail strip. However, theupper hammer may be controlled at will to make one or two printingstrokes. during each opera tion of the machine. When the upper hammermakes two printing strokes, the first impression is made upon an issuingticket, and after this ticket is ejected from the path of the hammer theimpression is duplicated on the permanent detail strip. When the upperhammer is positioned to make only one printing stroke, the feed of theissuing ticket is disabled and the impression is made on the permanentdetail strip.

As the issuing ticket is only about half as wide as the permanent detailstrip and covers only a part of the type carriers, it is necessary toprovide means to prevent a double impres-- sion being made upon the partof the detail strip not covered by the issuing ticket when the upperhammer makes two printing strokes. This is accomplished by meansof ashiftable platen block carried by the upper impression hammer whichcooperates with the portion of the permanent detail strip and typecarriers not covered by the issuing ticket. Prior to the firstimpression, the shiftable platen block is moved away from the typecarriers to prevent an impression being made on the permanent detailstrip at this time. Prior to the second printing stroke of the hammerthe movable impression block is shifted back to effective position.

The impression hammers disclosed herein are actuated by strong springs,which arecocked by a camming device and suddenly released. Just beforethe hammers contact the record material, the action of the strong springis abruptly terminated; the momentum of the hammers being sufficient tocomplete the impression stroke. The force of the impact of the resilientplaten blocks against the type carriers is sufficient to cause thehammers to rebound more or less violently and this rebound reactsagainst the spring actuating means sufficiently to make a light secondimpression stroke, which almost invariably blurs the record material. Inthe present application, mechanism is disclosed which makes itimpossible for the hammers to make a rebounding repeat stroke.

For a complete disclosure of the machine and particularly the printingmechanism to which the instant invention is applied, reference may behad to the parent application cited at the beginning of thisspecification.

DETAILED DESCRIPTION Type wheels Referring to Fig. 1, groups of typewheels 515 and 516 are rotatably supported on rods 5'11 and 518projecting from a printer frame (not shown) suitably secured to a rightside frame 36 and properly spaced therefrom. A shaft 215 journaled inthe main frames of the machine, and a plurality of telescoping tubes 214supported by said shaft extend from the accumulating section of themachine through the frame 30 and into the printing mechanism. The shaft215 and the tubes 214 have fast on the outer ends thereof gears 286meshing with pinions 581, one of which is secured on the side of each ofthe type wheels 515. The gears 2811 are also connected by intermediategears 582, to pinions 584 secured to each of the type wheels 516. Bythis means the differential positioning of the shaft 215 and tubes 214,imparted thereto by the machine differential mechanism, is transmittedto the type wheels 515 and 516 and sets these wheels to print characterscorresponding to the depressed amount keys in adding operations or thetotalizer wheels in totalizing operations.

A reversible inking ribbon 585 is alternatively unwound from and woundonto spools 586 and 581 supported respectively on studs 588 and 589projecting from the printer frame (not shown). The inking ribbon 585 isdirected by various studs and plates carried by an ink ribbon supportplate (not shown) between the type wheels 515 and 516 and theirrespective impression hammers. Mechanism is provided to feed the ribbonand to reverse the direction of travel of said ribbon. However, suchmechanism is not disclosed herein, but reference may be had to the U. S.Patent No. 1,929,652 issued October 10, 1933 to William H. Robertson,for a full disclosure of this mechanism.

Impression hammers The printing mechanism of the instant machineincludes a lower impression hammer 612 and an upper impression hammer613 pivoted respectively on studs 363 and 622 secured in the frame 36and carrying respectively resilient impression blocks or platens 611)and 611. A spring 616 is tensioned to urge the hammer 612counterclockwise to normally maintain a stud 611 in a downwardlyextending arm 614 of said hammer in contact with a projection 618 of ahammer operating arm 619 fulcrumed on the stud 303 and urged clockwiseinto contact with a stop stud or abutment 621 by a comparatively strongspring 620. A downwardly extending arm 625 of the hammer 613 carries astud 624 normally maintained in contact with a projection 626 of ahammer operating lever 621 loose on the stud 622, by a spring 623tensioned between said lever 621 and said arm 625. A strong spring 628,one end of which is attached to a rearwardly disposed arm of the lever621 urges said lever counterclockwise to normally maintain a roller 636on a forwardly extending arm 631 of said lever in contact with theperiphery of a hammer operating cam 632 secured on the main drive shaft216.

The main drive shaft 216 makes a complete counterclockwise revolutioneach machine operation and during this rotation lobes 633 and 534, onthe cam 632, in cooperation with the roller 6311 rocks the lever 621 andthe hammer 613 clockwise, flexing the spring 628. The arm 631 carries astud 635 which in cooperation with a projection 636 of the arm 619imparts counterclockwise movement to said arm 6 I 9 and the hammer 612to flex the spring 620 when the lever 621 receives clockwise movement asexplained directly above.

During rotation of the shaft 216 the lobes 633 and 634 move beyond theroller 636 and into contact with a nose 631 of the arm 631. When thenose 631 rides off the lobes 633 and 634 the springs 628 and 62D sharplyretract the lever 621 and the arm 619 until such movement is arrested byinto contact with the type wheels to record the 5:7

transaction.

It is desirable that the impression hammer 612 make only one printingstroke to make a single impression upon an issuing detail strip 112,while the hammer 613 is making two printing strokes. The hammer 612 isprevented from making the first impression stroke by the high portion ofa segment 638 secured to the cam 632 in cooperation with an arcuatesurface of a projection 639 of the arm 619. During rotation of the mainshaft 216 the high portion of the segment 638 passes under theprojection 639 before the nose 631 rides off the first lobe 633 of thecam 632. This blocks clockwise imprinting movement of the arm 619 andthe hammer 612 under influence of the spring 620 and it is thereforeevident that said hammer 612 is thus prevented from making the initialimprinting movement in unison with the hammer 613. Just before the nose631 rides off the lobe 634 to effect a second impression stroke of thehammer 613, the high surface of the segment 636 moves beyond theprojection 639, thus permitting the hammer 612 to move in unison withthe hammer 613 during its second printing stroke to make a singleimpression upon the issuing detail strip 112.

Mechanism to prevent rebound of the printing hammers When the hammers612 and 613 (Fig. 1) make a printing stroke, sharp contact of theirrespective platens 6111 and 611 with the type carriers and theresiliency of said platens causes said hammers to rebound sharply. Thiscauses the studs 611 and 624 to contact the projections 618 V and 626with suiiicient force to slightly rock the arms 619 and 62? against thetension of their respective springs 62!] and 628. The resulting returnmovement of the arms 619 and 631 is sufficient to cause the hammers 612and 613 to make a second light impression stroke, commonly referred toas a rebound stroke, which generally results in a blurring or smudgingof the first impression made on the record material. In the presentmachine this undesirable condition has been overcome by means ofindividual rebound preventers associated with each of the hammers. Theserebound preventers positively block any rebounding movement of theimpression hammers subsequent to an impression stroke. Both of therebound preventers operate upon the same principle, but due todifference of structure therein it is deemed advisable to describe eachof them in detail.

A flattened pin 645- on a downwardly extending arm 646 of the hammer 6I2normally lies in a recess formed in the upper edge of a rebound.preventing arm 641 (Figs. 1 and 3) pivoted on a stud 646 extendingbetween the frame 36 and the printer frame (not shown). The pin 645 alsolies within a larger recess in a detent slide 649, slidably supported bythe stud 648 and a stud 656 in the arm 641, said recess being largeenough topermit relative movement of the stud 645 thereto.counterclockwise cocking movement of the hammer 6I2 causes the stud 645in cooperation with an inclined wall of the recess in. the arm 641 torock said arm and the slide 649 counterclockwise against the tension ofa spring 653. Counterclockwise movement of the slide 649 moves aprojection 652 thereon below a flattened stud 651 secured in the frame30. Immediately thereafter continued counterclockwise movement of thearm 6I2 causes the stud 645 to engage the rearwardly disposed wall ofthe recess in the slide 649 to shift said slide rear.- wardly to movethe projection 652 thereof directly underneath. the stud 65L This.retains the forward wall. of the recess in the arm 641 out of the pathof the stud 64,5 upon return printing movement of the hammer 6I2' underinfluence of the spring 620' and allows said stud to. engage the forwardwall of the recess in the slide 649 to shift said slide forwardly tomove the projection 652 out of the path of the stud 65I. The spring 653immediately returns said slide and the arm. 641. upwardly until the topedge of the arm 641 contacts. the stud645. When the printing hammer 612'recoils from its impact with the type carriers, in the manner explainedabove,. the stud 645 moves off. the top edge of the arm 641 and into therecess therein. permitting said arm and the slide 649 to be returnedfull. distance upwardly by the spring 653 to. the position here shown.This moves the forward wall of the recess in the slide 641 in the pathof the flattened surface of the stud 645 to positively block re--bounding. movement of the hammer M2.

The rebound preventer for the hammer 6I3 (Figs. 1 and 2) functionssimilarly to the rebound preventer for the hammer 6I2. However, due tothe fact that this rebound preventer varies in structure from the onejust described, it is deemed advisable to give a detailed descriptionthereof. When the lobes 633 and 634 of the cam 632 retract the hammer6I3 clockwise, preparatory to a printing stroke of said hammer, a stud654 in an extension 655 of said hammer in cooperation with an angularsurface on a rebound preventing lever 656, rotatably' supported on astud 651 secured in the frame 36, rocks said lever clockwise. Clockwisemovement of the lever 656 is transmitted to a detent slide 659, slidablymounted by means of slots therein in. cooperation with the stud 651 anda stud 658 in a rearward arm of said lever 656,. by means of said stud658. Clockwise movement of the lever 656 and the slide 659' flexes aspring 660 and rocks a shoulder 66I= of said slide 6.59 out of the pathof or beneath a stud 662 projecting from the frame 30. Continued aclockwise movement of the hammer 6I3 causes the stud 654 to engage therearward wall of a notch in the forward end of the slide 659 and. shiftssaid slide rearwardly to move the shoulder or step 661 beneath the stud662, to restrain return movement counterclockwise of the lever 666 andslide 659 under influence of the spring 666 when the hammer starts itsimprinting movement counterclockwise. The stud 662 (Fig. 2) retains theslide 659 and the lever 656- in clockwise positionduring the greaterpart of the imprinting stroke of the hammer 6I 3 until the stud 654moves beneath a hook-shaped projection 644 of said lever 656. Near thetermination of its counterclockwise movement the stud 654 engages theinner wall of the notch in the slide 659 and shifts said slide forwardlyto move the shoulder 66! from beneath the stud 662, thus permitting thespring 660 to return the lever 656 counterclockwise until the projection644 rests on top of the stud 654 Recoil clockwise of the hammer 6I3caused by impact of the platen 6 with the type carriers causes the stud654 to ride off of the lower surface of the projection 644 and thespring 660 immediately returns said lever 656 to normal position toplace the projection 644 in the path of the stud 654 to positively blockrebounding movement of the hammer 6I3.

Control of ticket printing and issuing mechanism by transaction keysDepressing the transaction key 44 (Fig. 5) controls the printingmechanism to issue a permit ticket 691- (Figs. 1 and 4). Depressing anyone of the three keys 45, 46 or 41 operatesmechanism that prevents thepermit ticket printing hammer 6I3 from making its first impressionstroke and renders ineffective the permit ticket feeding mechanism.

The keys 45, 46 and 41 eachcarry a stud I03 which cooperate respectivelywith the angular camming surfaces of three tooth-shaped projections of asector I65 formed on the outer end of an arm I66 fulcrumed on adifferential supporting shaft I49 journaled in the main frames of themachine. Depressing any one of the keys 46, 46 or 41 by means of thestud I63 in cooper ation with the angular camming surface rocks thesector I65 and the arm I66 clockwise which movement by means of a linkI61, connected between the sector I65 and. the upper end of an arm I68,is transmitted to said arm I68. The arm I68 is secured to a short shaftI69 journaled in the right frame 30 and a bracket not shown.Consequently said shaft moves in unison with the arm I 68. Clockwisemovement of the arm I68 shifts a pitman 663 rearwardly, the forwardendof said pitman being pivoted at 615 to said arm I66 and the rearward endof said pitman being slotted to embrace a stationary stud 664 projectinginwardly from the frame 30. Rearward movement of the pitman 663 causes adownward projection 665 thereof in cooperation with a stud 666 inan arm661 loose on a rod 566 supported by the main frame, to shift said arm661 clockwise.

The arm 661 is flexibly connected by a spring 668 to a hammer arrestinglever 669 also. loose on the rod 566. The spring 668 normally maintainsa raised surface of the arm 661 in contact with a stud 616 secured inthe lever 669. The lever 669 carries a stud 610 which extends within aslot 61I in the lower end on a link 612 (see also Fig. 1) the upper endof said link being pivotally connected to a crank 613 secured on a shaft439 journaled in the right and left indicator end frames, the right one(35) of which is here shown in dot and dash lines.

counterclockwise rotation of a shaft 213 (Fig. 6), as explained fully inthe parent application, rotates companion plate cams 421 and 426 inunison therewith.

The peripheries of the cams 421 and 428, in cooperation with theirrespective rollers 429 and 436 on the Y-shaped'arms of a cam lever 43Ifulcrumed on a rod 432, rocks said lever first counterclockwise and thenback to normal position, as here shown.

Oscillating movement of the lever 43I first lowers and then raises apitman 433, the lower end of which is pivoted to said lever 43I, and theupper end of said pitman being guided by a slot therein in cooperationwith a rod 435 extending between the indicator frames. Oscillatingmovement of the pitman 433 by means of a stud 436 in the upper endthereof, in cooperation with a horizontal slot in a crank 436 secured onthe shaft 439 rocks said crank and said shaft first counterclockwise andthen back to normal position. Initial movement counterclockwise of theshaft 439 (Figs. 1 and 5) and the crank 613 moves the link 612downwardly thus allowing the spring 668, which has been tensioned byclockwise movement of the arm 661 under influence of the pitman 663, tomove the lever 669 in unison with the link 612. Clockwise movement ofthe lever 669 moves a surface 614 on the broad end thereof opposite thestud 654 in the hammer 6I3 to block clockwise retracting or cockingmovement of said hammer, thereby preventing said hammer from beinginfluenced by the first lobe 633 of the cam 632 in cooperation with thelever 621 and the spring 628.

Before the second lobe 634 of the cam 632 imparts cocking movement tothe lever 621 the companion cams 421 and 428 in cooperation with thelever 43I shifts the pitman 433 upwardly to return the shaft 439, thecrank 613 (Fig. 1) and the link 612 to normal position as here shown.Return movement upwardly oi the link 612 (Fig. 5) returns the disablinglever 669 counterclockwise to normal position to remove the surface 614thereof from the path of the stud 654. The hammer 6I3 then makes itssingle printing stroke under influence of the lobe 634 of the cam 632 tomake an impression upon the permanent detail strip 199 (Fig. 1) which isunwound from a supply roll, (not shown) threaded around various guidestuds and two rollers 805 turnably supported by plates 896 (see alsoFig. 7) secured to the hammer 6I3 and finally wound upon a receivingroll (not shown). For a complete description of the permanent detailstrip feeding mechanism reference may be had to the parent Patent No.2,056,485.

The transaction keys 45, 46 and 41 (Fig. 5) are stay-down keys and aretherefore not influenced by the automatic key releasing mechanism. It istherefore evident that as long as one of these keys is depressed thepitman 663 retains the arms 661 in clockwise position to tension thespring 668 and consequently the lever 669 will operate each machineoperation to block the first imprinting movement of the hammer 6| 3.Depressing the transaction key 44, in a manner explained in the parentapplication, releases any depressed transaction key 45, 46 or 41, thuspermitting a spring I1I (Fig. 5) in cooperation with a crank I12 securedto the shaft I69 to return said shaft, the lever I68, and the pitman 663and the sector I65 to normal position as here shown. The tensioning arm661 returns in unison with the pitman 663 to relieve the tension of thespring 668, thus preventing clockwise movement of the lever 669 when thelink 612 is lowered in the manner explained above. When the lever 669remains in its ineffective position, the slot 61I in the link 612prevents the up-and-down movement of said link from imparting movementto the stud 619 and lever 669. It is therefore to be understood thatwhen the machine is operated with the transaction key 44 depressed, thehammer 6I3 is free to make two impression strokes, the first of whichcauses a record of the transaction to be imprinted upon the permitticket 691 (Figs. 1 and 4) and the second upon the permanent detailrecord strip 199 (Figs. 1 and 8).

Shiftable platen for the permit ticket printing hammer By referring toFigs. 1 and 7 it will be seen that the permanent detail strip 199 isguided by the rollers 965 around the head of the hammer 6I3 andmaintained in close relationship to the platen block 6| I. It willlikewise be observed that the issuing ticket 691 is fed upwardly betweenthe inking ribbon 585 and the permanent detail strip 199. Therefore whenthe transaction key 44 (Fig. 5) is depressed, the web of the issuingticket 691 is fed upwardly between the ribbon 585 and the permanentdetail strip 199. Consequently the first impression will be made on theissuing ticket 691. Immediately after being imprinted the ticket 691 isejected from the machine, thus permitting the second impression to bemade on the permanent detail strip 199. When one of the transaction keys45, 46 or 41 is depressed, the feed for the issuing ticket 691 isdisabled; consequently the web of said ticket is not fed upwardlybetween the ribbon and the permanent detail strip. In such a case thereis no need for two impression strokes of the hammer M3 and therefore thefirst impression stroke of the hammer is disabled in the mannerexplained above and the second impression stroke causes the transactionto be recorded upon the permanent detail strip 199.

By referring to Fig. 7 it will be noted that the ticket 691 covers onlypart of the type wheels 516 and is only about half as wide as thepermanent detail strip 199. Therefore to prevent the first stroke of thehammer from making an imprint upon the portion of the permanent recordstrip not covered by the issuing ticket 691 a shiftable platen isprovided which is moved to an ineffective position during the firstprinting stroke of said hammer. The shiftable platen and associatedmechanism will now be described.

Directing attention to Figs. 1, 5 and '1, the impression hammer 6I3 hasat its upper end a laterally extending table 685 with an upwardlyextending rib 684 extending the full width of the type wheels 516.Substantially half of the rib 684 (Fig. 7) is channeled to receive theimpression block 6 while the other half of said rib is cut away toprovide room for a platen supporting bar 68I channeled to receive aplaten block 689 adapted to make imprints upon the portion of thepermanent detail strip 199 not '68! secured to the table 685.

centric shaft 66L covered by the issuing ticket 691. The platen bar 68!is supported by the forward ends of plungers 682 and 683 which extend.-through holes in the rib 684 and are further supported by holes in ears686 projecting from a bracket Compression springs 688 wound around theplungers 682 and 683 are confined between the rail 684 and collars 689one of which is secured to each of the plungers 682 and 583. I Thesprings 688 urge the plungers 682 and 683 rearwardly as viewed in Fig. 1and downwardly as viewed in Fig. '7, to normally maintain rollers,turnably mounted in slots in the ends of said plungers, in contact withthe peripheries of symmetrical cams 696.

The cams 690 are secured on a shaft 69I turnably and shiftably supportedin substantially horizontal slots in a pair of upturned ears 692 of thebracket 681. Loose on the shaft 69] are two eccentrics 105, which incooperation with studs 168 in extensions of the ears 692 provide a meansof adjusting the shaft 69! and the cam 690 in relation to the plungers682 and 683; thus providing a means of adjusting the platen bar Bill andthe platen 680 relatively to the type wheels 516 to control theimpression. The eccentrics 105 have knurled rims 106 which provide aneasy means of adjusting said eccentrics, and which in cooperation withretaining clips 10! (Fig. 1) secured to the table 685 provide a means ofretaining the eccentrics in adjusted position.

Secured on the righthand end of the shaf 69! (Figs. 1 and'l) is a crank695 connected by a link 694 to an arm 693 secured on a shaft 426journaled in the indicator frame. Also secured on the shaft 426 (Fig. 6)is a crank 431 slotted to receive the stud 436 in the pitman 433.

As explained hereinbefore, depressing the transaction key 44 (Fig. 5)conditions the printing mechanism to make two impressions, one on theissuing ticket 691 (Fig. 7) and the other on the permanent detail strip199. The first'impression is made on the ticket 691 after which saidticket is severed from its web and ejected from the machine, and thesecond impression is made on the permanent detail strip 199. Prior tothefirst impression stroke of the hammer 6l3 the cams 421 and 428 (Fig. 6)in cooperation with the lever 43l shift the pitman 433 downwardly torock the crank 43'! and the shaft 426 a slight distance clockwise. Thearm 693 (Fig. 1) and the link 664 transmits clockwise movement of theshaft 426 to the arm 695 and the ec- Clockwise movement of the shaft 69lmoves the high portions of the cams 696 away from the plungers 682 and683 whereupon the springs 688 (see also Fig. 7) shift said plungers andthe platen bar 68I away from the type carriers so that the firstimpression will not be made on the portion of the detail strip 199 notcovered by the issuing ticket 691. Immediately after the firstimpression is completed and before the second impression, the cams 421and 428 and connected mechanism return the shafts 426 and Billcounterclockwise to normal position as here shown, whereupon the cams690 restore the platen bar Bill to printing position so that the secondimpression will be made upon the full width of the permanent recordstrip 199.

The mechanism just described for shifting the platen bar 68l (Fig. 7)out of and into printing position functions every machine operation, andwhile it is unnecessary for this mechanism to operate when the printingmechanism has been conditioned by depression of one of the transactionkeys 45, 46 or 41 (Fig. 5) for a single impression, still its operationat this time does no harm whatever.

While the form of mechanism herein shown and described is admirablyadapted to fulfill the objects primarily stated, it is to be understoodthat it is not intended to confine the invention to the one formorembodiment herein disclosed, for it is susceptible of embodiment invarious forms, all coming within the scope of the claims which follow.

What is claimed is:

1. In a machine of the class described; the combination with amanipulative device; a printing hammer; and means to cause the printinghammer to deliver a plurality of impression blows at each operation ofthe machine; of normally idle means to block the printing hammer againstoperation; a tension member to shift the blocking means toeffective-position; means controlled by the manipulative device toactuate the tension member; and means to release the blocking means formovement into blocking position and then restore said blocking meansinto idle position.

2. In a machine of the class described, the combination with a printinghammer; a manipulative device; and means to cause the hammer to delivera plurality of impression blows at each operation of the machine; ofnormally idle preventing means to render the printing hammerineffective; means controlled by the manipulative device to control theoperation of the preventing means; and means timed with relation to thehammer-operating means, to release the preventing means for operationprior to an operation of the hammer and to restore the preventing meansto ineffective position after the operation of the hammer.

3. In a machine of the class described; the combination with amanipulative device; a printing hammer; and means to cause the hammer todeliver a plurality of impression blows at each operation of themachine; of a normally ineffec tive means to disable the hammer; atension arm; a spring connecting the disabling means and the tensionarm; means operated by the manipulative device to shift the tension armto place additional tension on the spring; and means normally inposition to restrain said disabling means against operation and operableduring a machine operation to release said disabling means at apredetermined time.

4. In a machine of the class described; the combination with amanipulative device; a printing hammer; and means to cause the hammer todeliver a plurality of impression blows at each operation of themachine; of a normally ineifective means to disable the hammer; meanscontrolled by the manipulative device to operate the disabling means;and restraining means to release the disabling means for operationbefore the time of the first impression blow of the hammer and torestore the disabling means to ineffective position before the time ofthe second operation of the hammer.

5. In a machine of the class described; the combination with amanipulative device; a printing hammer; and means operable at eachoperation of the machine to cause the printing hammer to deliver aplurality of impression blows; of a normally idle means to disable thehammer; a tension arm, a spring connecting the tension arm and thedisabling means; a pitman; means controlled by the manipulative deviceto actuate the pitman and rock the tension arm; a link coacting with thedisabling means to restrain the disabling means against operation; andmeans to operate the link to release the disabling means to the actionof the spring before the time of occurrence of one of the impressionblows and to restore the disabling means to idle position thereafter.

6. In a machine of the class described; the

combination with type elements; a printing hammer; and a platen; ofplungers carried by the hammer to adjustably support the platen;resilient means tending to retract the adjustable platen; a shaft;restraining members on the shaft coacting with the plungers tonormallymaintain the adjustable platen in printing position; and means to rockthe shaft and the restraining members to release the plungers to theaction of the resilient means, whereby the platen is withdrawn fromprinting position.

7 In a machine of the class described, the combination with a printinghammer; and means to cause the hammer to deliver a printing blow; ofmeans to prevent rebound of the hammer against the printing face,including a hammer-arresting member normally in arresting position; alatching member associated therewith for relative movement in one lineonly to latch the member out of arresting position; and means on theprinting hammer cooperable with the hammerarresting member and thelatch, whereby the member is moved out of and into arresting positionand the latch is moved into and out of latching position.

8. In a machine of the class described, the combination with a printinghammer and means to actuate the hammer, of means to block the hammer,movable from a normally ineffective position into an effective position;normally ineffective means to move the blocking means to said effectiveposition; means to render the moving means effective; and meanscooperating with the blocking means to release said blocking means tomove to effective position under the influence of the moving means, andto thereafter return the blocking means to ineffective position.

9. In a machine of the class described, the combination with a printinghammer and means to actuate the hammer, of means to block the hammeragainst actuation, movable from a normally ineifective position into aneffective position; a member to normally retain the blocking means inineffective position; a normally ineffective means rendered. effectiveupon withdrawal of the member to move the blocking means to effectiveposition; and means to operate the member to release the blocking meansto move to e1- fective position under influence of the moving means,said operating means also adapted to return the blocking means toineffective position.

10. In a machine of the class described, the

combination with a printing hammer and means to disengage the memberfrom the retaining means; and means to move the element into effectiveposition to obstruct rebounding printing movement of the hammer when itis released by the hammer.

11. In a machine of the class described, in combination with a printinghammer, means to retract the hammer, and a spring to operate the hammerto effect a printing operation, of a pivoted arm provided with ashoulder normally in the path of the hammer to prevent rebound of 1 thehammer after a printing operation; a slide connected with the arm topivot with the arm and to move relatively thereto; a stop; a cam on thearm coacting with the hammer as the hammer is retracted towithdraw theshoulder from the path of the hammer and to move the slide relatively tothe stop; a shoulder on the slide coacting with the hammer whereby theslide is moved by the hammer into a position to engage the stop whereinthe arm is held out of the path of the hammer as the hammer makes itsprinting operation; an abutment on the slide in the path of the hammerwhereby the hammer moves the slide to disengage the slide from the stopas the hammer makes its printing operation; and a restoring spring torestore the arm and slide into their initial positions when the slide isdisengaged from the stop to position the shoulder on the arm into thepath of the hammer to arrest the hammer as it rebounds from itsoperating spring after a printing operation. 1

WILLIAM H. ROBERTSON.

